1. Technical Field
The present invention relates to the structure of a light-emitting device that employs a light-emitting element such as an organic light-emitting diode element.
2. Related Art
A light-emitting device in which a large number of light-emitting elements are arranged in a matrix has been proposed. Each light-emitting element includes a first electrode, a second electrode, and a light-emitting layer lying between both electrodes. JP-A-2002-352963 discloses a top emission light-emitting device that includes a light-transmissive conductive layer shared by a plurality of light-emitting elements as their common second electrode. The device further includes auxiliary interconnects formed in the gaps between the light-emitting elements. The auxiliary interconnects are formed of a material having a resistivity lower than that of the second electrode. Due to this configuration, if the second electrode is formed of a high resistance material, the voltage drop in the second electrode is reduced. Therefore, the voltage applied to each light-emitting element is uniformized, and nonuniformity in gradation is controlled.
Most low resistance metals used as the material of the auxiliary interconnects block light. Therefore, when the auxiliary interconnects are disposed on the light emission side (light extraction side) of the light-emitting elements, the aperture ratio is restricted by the auxiliary interconnects. The “aperture ratio” is the ratio of the area of regions from which light is actually emitted, to the area of tale region where a plurality of light-emitting elements are arranged. If the width of the auxiliary interconnects is reduced, a high aperture ratio can be maintained. In this case, however, due to the increase in resistance value of the auxiliary interconnects, the voltage drop of the second electrode cannot be sufficiently controlled.
In some cases, in order to prevent the auxiliary interconnects from overlapping with the light-emitting elements even if there is an error in the positions of the auxiliary interconnects, a space (hereinafter referred to as “margin region”) is provided between the region where each auxiliary interconnect is to be formed as designed and each light-emitting element. Since neither auxiliary interconnect nor light-emitting element is formed in the margin region, it is more difficult both to increase the aperture ratio and to sufficiently control the voltage drop.